2x=3y=42

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by Brent@GMATPrepNow » Mon Oct 15, 2012 9:21 pm
humpback wrote:if w,y,z are positive numbers and 2x=3y=4z, then the value of x+y+z is how many times the value of x
Algebraic approach

If 2x=3y, then y = (2/3)x
If 2x=4z, then z = (1/2)x

So, x+y+z = x + (2/3)x + (1/2)x
= (6/6)x + (4/6)x + (3/6)x
= (13/6)x

The question asks, "The value of x+y+z is how many times the value of x?"

As you can see, x+y+z is 13/6 times the value of x.

Cheers,
Brent
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GMAT/MBA Expert

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GMAT Instructor
Posts: 16207
Joined: Mon Dec 08, 2008 6:26 pm
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by Brent@GMATPrepNow » Mon Oct 15, 2012 9:24 pm
humpback wrote:if w,y,z are positive numbers and 2x=3y=4z, then the value of x+y+z is how many times the value of x
Plugging in Numbers approach

Find values of x, y and z that satisfy the equation 2x=3y=4z

One set of values is x=6, y=4 and z=3

So, x+y+z = 6+4+3 = 13

The question asks, "The value of x+y+z is how many times the value of x?"

Since x=6, we can see that x+y+z (aka 13) is 13/6 times the value of x (aka 6).

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
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